Diet, Exercise & Weight Loss Study

Exercise and diet in obesity treatment:
an integrative system dynamics perspective.

Diet-Exercise-Weight Study - Aim
Demonstrate the utility of System Dynamics computer modeling to study
and gain insight into the impacts of physical activity and diet on weight
gain and loss.

Diet-Exercise-Weight Study - Methods
A holistic System Dynamics computer model integrates the processes of
human metabolism, hormonal regulation, body composition, nutrition, and
physical activity. These processes are not independent of one another,
and the model captures the complex interdependencies between them in the
regulation of body weight and energy metabolism.

Diet-Exercise-Weight Study - Results
In one experiment, weight loss from a moderate level of daily exercise
was slightly less than the loss from dieting. Although exercise did have
a favorable impact on body composition by protecting against the loss
in fat-free mass (FFM), it, however, failed to blunt the drop in resting
energy expenditure (REE) that accompanies diet-based weight loss. The
smaller loss in FFM did indeed induce a smaller drop in REE, however,
the preservation of FFM also affected a relatively larger loss in FM,
which, in turn, induced a larger adaptive reduction in the metabolic rate.
The two adaptations almost totally offset one another, causing minimal
differences in REE.

In a second experiment, exercise regimens
of moderate- to high-level intensity proved counterproductive as weight-reducing
strategies. However, when the diet was changed from a balanced composition
to one that was highly loaded with carbohydrates, it became possible to
sustain the intense exercise regimen over the experimental period and
achieve a significant drop in body weight.

Diet-Exercise-Weight Study - Conclusion
The results underscore the significant interaction effects between physical
activity, diet, and body composition and demonstrate the utility of computer-based
experimentation to study, gain insight into, and make predictions about
their dynamics.

Weight Loss News
Theories about how to lose weight, how to reduce obesity and general weight
management are constantly changing along with ideas about which weight
loss diet program is best and so forth. At present, however, a balanced
diet combined with regular exercise remains the favorite weight loss strategy
of most dietitians and weight loss experts.